No, 85 is not a prime number. It is a composite number: it ends in 5, so it is divisible by 5.
85 has divisors other than 1 and itself. The smallest is 5: 85 ÷ 5 = 17.
Prime factorization: 85 = 5 × 17.
| Number | Prime? |
|---|---|
| 81 | No, 3 × 3 × 3 × 3 |
| 82 | No, 2 × 41 |
| 83 | Yes |
| 84 | No, 2 × 2 × 3 × 7 |
| 86 | No, 2 × 43 |
| 87 | No, 3 × 29 |
| 88 | No, 2 × 2 × 2 × 11 |
| 89 | Yes |
More about 85: factors of 85 · 85 squared · square root of 85 · 85 in binary · 85 in Roman numerals.
Another number? Use the prime number checker for any value, or see the list of prime numbers.